Core box for pistons



Patented Apr. l0, ll923 'tp Wt h ha ail DANIEL W. CLARK, OI LOS ANGELES, CALIFORNIA.

CORE BOX FOR PISTONS.

Application :filed December 3, 1921.

July 20.` 1920; and May 17, 1921.

In the manufacture ot light weight pistons has become essential, in order to provide a minimum thickness ot metal in the wall and head of the piston, to thoroughly reinforce the skirt and head for resisting: the shock and strain due to the operation oit pistons in an internal combustion ennine. lin order to provide reinforcing' ribs for this purpose. special core bones have been provided, as shown in the above named patents. whereby plates are movably held in the core bof: so as to be withdrawn therefrom after the core has been made, and prior to the disassemblingr of the core box, tor the purpose ot stripping; the ribs from the recesses in the core, so as to prevent damage being done to the core around said recesses.

ln the present invention it is an object to provide in addition to the usual character et the ribs and core torining,` means disclosed in the said patents, additional ribs around the wrist pin bosses, so as not only to thoroughly brace said bosses but to better reinforce the walls of the piston in the vicinity ot the bosses. @ne of the ribs oli' my improvement is arranged in a horizontal plane and is transversely disposed relative to the usual longitudinal ribs in the core box. In Order to form these rib recesses in the core it is necessary, and it is therefor an object of my invention to provide means for stripping these additional ribs from the core and for forming corresponding recesses in the core thereby.

It is a further object ot my invention to provide a modification and means for with drawing the longitudinal ribs Jfrom the core bor: in planes paralleling the axis ot the piston or core, and for withdrawing the relatively right angular ribs at the pinV bosses from the core box. Means is also Provided for adjustingthe head forming member relaf Serial No. 519,760.

tive to the skirt forming members of the core box, so as to regulate the length of the shirt and the distance trom the head to the center ot the pin bosses.

@ther minor objects may appear as the description progresses.

I have shown one practical embodiment ot my invention in the annexed drawings, in which:

Fig. l is an inverted elevation of my core box, partially in section, in a plane cutting` the center of one oit the wrist pin bosses.

2 is an inverted sectional elevation ot the seme. in a plane at right angles to Fig. l.

3 is a transverse sectional plan of the same in a plane cutting,r the wrist pin bosses.

Fig'. ef is a plan of the interior of the adustable end member for the core bon.

Fig. 5 is a perspective view of a piston slmwine` the ribs formed therein by means ot' my improved core box; and

6 is an elevation oit a core inade from a core box preparatory to the casting ot a piston therefrom.

shown in the drawings, the core comprises body split in the center and formed ot like members B, and B', with semi-cylindri l central portions l, l, forininp` a circular terior when positioned together for use, as shown in Fig. l, and having a core print forming' portion 3 one end thereot, with a flaring recess 4 corresponding to the and form ot the core print. Intermediate the hollow portions 2 and 4 ot' the body l provide an annular rib 5 which extends slightly inwardly from the inner periphery of the portion 2 and provides a restricted opening 6 between the hollow portions 2 and t. The core print forming members 3, 3, have matched lugs 7, 7, with apertures S, S. thereby, by means of which the two lil-:e halves oi the body may be caused to register when dowels or pins are inserted through said apertures.

rlhe body portions B and B have like bosses 9, 9, formed thereon in diametrical alinement at right angles to the abutting faces or" the body members, and said boses entend outwardly from the outer periphery ot the portions l of the body members for a substantial distance. Plugs P, P, are adapted tor insertion in the bores 10, 10, ot said bosses and have heads 11, 11, which abut the outer faces ot the bosses. Central reduced portions 12, l2, which slidably engage the bores 10, l0, ot said bosses are still further lto fit into the open end of the box for a substantial distance for reducing the diameter and areal of the recess 2 of the box at the head Where the piston ring grooves are provided. This construction permits ot a greater thickness of metal in the upper portion of the piston opposite the ring grooves and may be oit a length corresponding to the number oi: grooves provided in a piston.`

rfhe head H has a central boss 15, in Which the end 16 of a stem S is attached by threading or otherwise. and al Web 17 connects the boss with the annular portion 14 of said head, The Web portion of said head H is externally threaded to receive au adjustment ring R and said ring has a plurality7 of pins or screws 18 held therein and arranged so that the heads of said screws will conta-ct with the outer end of the core bei; body, when the head member H is ac'ljustedinwardly to a desired extent.

Now, it will 'be understood that the adjustment of the ring R- on the head will serve to 'regulate the distance the portion 14 of said head extends into the core box body, thus correspondingly regulating' the ring groove portion of a piston.

The stem S slidably carries a movable end member E which is bored at 19 to receive said stem and has a knob 20 on the outer end thereof by means of which said member may be inserted in or withdrawn from operative connection with the head H and body members B and B. Then said end member is in operative position, the inner tace of the annular Wall 21 thereof will abut the outer face of the annular ring R.

`A disc 22 is provided on the interior ot the member E in abutment With the web 23 of said member, and is bored to receive and adapted to be fixed to the stem S. Said disc has a plurality of radially formed slots 24, 24, etc., in which the ends of a plurality of plates 25, 25, etc., are adapted to be inserted, and held by means of set screws 26,

26, carried in the annular' portion 21 of end member E.

All of the ribs 25, with the exception ot thetwo ivhichintersect the Wrist piu. bosses 13, 13, are similar in size and form', and the outer ends thereof are of a Width substantially corresponding to the length or' the bosses 13, While the inner portions thereof are tapered so as to merge With the inner periphery of the core box at a point near the annular rib 5 thereof, as clearly shown in Fig. 2. i

so as to intersect said rib and to form in the core continuous recesses intersecting With the recess formed by the annular rib 27.

The outer edges 23 ot the ribs 25 are straight and closely fit the inner' periphery of the core box, and are adapted to slide thereover when the member is moved out- Wardly on the stem S. The pair oit' ribs 25 which intersect the Wrist pin'bosses 13 have their Widest portions extended substantially inwardly into Contact' with the periphery ol the bosses 13, and the innermost portions 29 thereof are tapered and reduced in size, and are adapted to slidably seat in slots 30 which are formed longitudinally through the bosses 13.

New, it will be observed that when a core is to be made by means ot my improved core box, preparatory to the manufacture ot a piston, the parts are positioned as shown in the drawings, and after the core is formed on the interior ot the box the end member E .may be moved slidably on the stem S tor a distance sufficient to completely Withdraw the ribs 25 `from the core, thus serving to strip the ribs from the core and prevent damage thereto. A'.lo this end the head member H is radially slotted at 31 so as to permit the movement of the ribs 25 therethrough and the slots in the head of the ribs register with those in the end member E.

As hereinbefore stated, it is desirable to brace the Wrist pin bosses 13 horizontally or transversely of the core box body, and tor this reason l provide plates or ribs 32, 32, Which are iixed centrally in the bosses 13, 13 and have their ends 33, 33, extended outwardly on opposite sides' of said bosses and tapered so as to abut the adjacent ribs 25, 25 on opposite sides 'of said bosses. T his is shown in Fig. 3.

v'lhe bosses 9, 9, on the body members B and B are slotted transversely so as to slidably receive the ribs y32, 32, and to permit the Withdrawal ot said ribs from the body in horizontal and radial planes after the ribs 25 have been stripped from the core. 1t will be observed by reference to Fig. 1 that the portions 32 extend through the bosses 13 and have apertures therein so as to permit the extension of the rib portions 29 therethrough when the core box is set up and it is necessary that the ribs 29 be removed from the core box before the plugs P can be Withdrawn.

In Fig. G I have shown a core of the character adapted to be formed in the core bon herein shown and described. Said core com prises a body C of sand and oil, or other ingredients usually provided in foundry practice. The core print 34 is formed by fill Lie

means of the portion 3 of the core box, and the adjacent groove 35 therein is formed by means oi' the annular rib 5. The longitudinal recesses 25 are termed by means of the longitudinal ribs The .transverse recesses 32 are termed by means ot the transverse ribs 32, and the wrist pin boss recesses 13 are formed by means of the members i3. lin the manufacture ot pistons such as is shown in Fig; 5, the core is tiret 'formed anc. then a mating` mold is torried by means ot a pattern which is slightlv larger than the core, the two halves of the mold being then placed together and metal poured in the space around tl core. Thus, the reduced portion lll ot the core will provide a correspondingly thiclr wall la on the piston, and the completed piston will then embody a relatively thin cast metal skirt 36 with inwardly extended pin bosses 3T, 37, on the interior thereof, and a plurality of longitudinal ribs 38, 3S, merging; with a central annular rib 39 on the head, and having; their reduced tapered portions extender downwardly on the skirt. rlhe pair oit ribs intersecting the pin bosses will be continued below the pin bosses, as at d0, and such portions will correspond to the lower portions ot the other ribs 38, while the transverse ribs ell will be formed at right angles thereto.

New, in operation, the members B and B are irst litted together so as to form a complete cylindrical unit, the plugs P, P, are then inserted in the bosses 9, and the head H in the open end of the body, thereafter the end member is moved inwardly on the stem S, so that the 25 carried thereby will be properly positioned on the interior ot the body B. rEhe members B and B beinO suitably clamped together, the sand and otner ingredients ot the core are thenplaced in the interior oil tl box and after a prelimiuary setting, the box is disassembled in order, the core is removed, and hardened and the casting; operation of the piston follows.

lllhile l have shown a practical form ot core box for illustrating; my present invention, l may modify and alter the same within thescope et the appended claims without departingfrom the spirit thereof.

What l claim is: y

l. il. core boi; comprising a body having diametricallv opposite aperturesA in the wall thereof, plugs detachably held in said apertures, and plates held in the inner ends of said plugs ant slidably movable therewith through said bot y, for the purpose described.

2. A core box comprising' a body having diametrieally opposite apertures in the wall thereof, plugs detachably held in said apertures, and platesl held in the inner ends of said plugs and slidably movable therewith through said body, and a plurality of other plates slidably held in said body and movable at right angles to said lrst mentioned plates, for the purpose described.

3. A core boi; comprising a body having diametrically opposite apertures in the wall thereof, plugs detachably held in said apertures, plates held in the inner ends of said plugs and slidably movable therewith through said body, and a plurality of other plates slidably held. in said body and movable at right angles to and through said tirst mentioned plates, tor the purpose described.

l. A core box tor pistons comprising a body member haa/iup` diametrically alined and outwardly extending bosses formed on the wall thereof, provided with alined bores therethrough, plugs slidably held in said bosses and having portions extending` sub stantially inwardly into said body, and diametrically disposed plates carried in the inner portions ot said plugs and also entending; substantially into the interior of. said body, for the purpose describer.

5. A core boi; for pistons comprising a body member having` diametrically alined and outwardly extending bosses formed on the wall thereof, provided with aline-d bores therethrough, plugs slidably held in said bosses and having` portions extending substantially inwardly into said body, diametrically disposed plates carried in the inner portions of said plugs and also extendingr substantially into the interior of said body, and a plurality oit other plates slidably held in said body and disposed at right angles to said first mentioned plates, tor the pun pose described.

6. A core .box for pistons comprising; a body member having' diametrically alined and outwardly extending bosses formed on the wall thereof, provided f'ith alined bores therethrough, plugs slioably held in said bosses andY having; portions extending` substantially inwardly into said body, diametrically disposed plates carried in the inner portions otl said plugs and also extending` substantially into the interior of said body, and a plurality ot other plates on the interior of said body disposed at right angles to and movable through said iirst mentioned plates, tor the purpose described.

7. A core boi: for pistons comprising a sectional body, external bosses on said body having bores extending; horizontally therethrough, plugs insertablein said b ores hav ing extensions projecting` substantially into the interior of said body, and having diametrically disposed ribs extending outwardly therefrom for providing a corresponding` recess on the core, said bosses being slotted to receive said ribs, and said plugs being removable from the core through said body.

8. A core boX for pistons comprising a sectional body, external bosses on said body, having bores extending horizontally thereloo through, plugs insertable in said bores having extensions projecting substantially into the interior of said body, and having diametrically disposed ribs extending outwardly therefrom for providing a corresponding recess on the core, said bosses being slotted to receive said ribs, and said plugs being removable from the core through said body, and a plurality of other ribs disposed at right angles to the ribs in said plugs, and having portions extending through said plugs for forming corresponding recesses in the core.

9. A core box for pistons comprising a body having plugs laterally movable in the Wall thereof, and a pair of relatively right angularly disposed plates extending through each of said plugs on the interior of said body for forming corresponding rib recesses in the core.

l0. A core box for pistons includinov separable body members diametrieally alined, plugs rei'novably held therein, a head forming member closing one end of said body and adjustable relative thereto, an end member adj ust-able relative to said head member and having a plurality of plates carried thereby and slidable through said head member into the interior of said body for forming corresponding rib recesses in the core, the inner ends of said plugs being extended substantially into the interior of said body, and certain of said plates being extended therethrough for continuing` the rib recesses on opposite sides of said plugs.

1l. A core box for pistons including separable body members, diametrically alined plugs removably held therein, a head forming member closing one end of said body and adjustable relative thereto, an end member adjustable relative to said head member and having a plurality of plates carried thereby and slidable through said head member into the interior of said body for forming corresponding rib recesses in the core, the inner ends of said plugs being extended substantially into the interior of said body, certain of said plates being extended therethrough for continuing the rib recesses on opposite sides of said plugs, and relatively right angularly disposed plates carried in said plugs for forming transverse rib recesses on the core, as described.

l2. A core box for pistons comprising a hollow body member, a head adjustable into one end of said body, a ring on the outer end of said head for adjusting the thrust of said head into said body, and a plate holding member concentrically mounted on said head and having a plurality of plates slidable through said head and into said body, for the purpose described.

18. A core box for pistons comprising a pair of like body members, havinga cylindrical support, a core print forming member on one end thereof, a head forming member on the other' end thereof, an end member adjacent to said head and held relative thereto, a plurality of plates carried in said end member and slidable through said head member and into the interior of said body for forming a corresponding ribrecess longitudinally of the core, a pair of diametrically alined bosses on said body members, plugs insertable in said bosses and having reduced extensions on the inner ends thereof projecting substantially into the interior of said body for forming Wrist pin boss recesses in the core, a transverse rib recess forming member carried in the end of each of said bosses, the longitudinal plates at said plugs being extended through said bosses, `for the purpose described.

lll. A core box for pistons including a pair of like semi-cylindrical body members, capable of being held together' in a core forming operation, a head forming member on one end of said box, a core print forming member on the other end thereof, a plurality of longitudinal plates commonly supported and slidable through said head member into the interior of said core box for forming longitudinal rib recesses on the core, a pair'of diametrically alined bosses formed on the exterior of said core box, removably held plugs in said bosses having Wrist pin boss recesses forming portions on the inner ends thereof, plates carried in said bosses and disposed at right angles to said longitudinal plates for forming transverse ribs on the peripheries of said core, adjacent said Wrist pin boss recesses, said external bosses being slotted to slidably receive said plates.

' DANIEL W.VCLARK. Witnesses:

CHAs. BAGG, IRENE BREEN. 

